The cardiac device field has been dogged by federal investigations and legal actions for years. Major manufacturers, such as Boston Scientific, Johnson & Johnson, Medtronic and St. Jude Medical, have been among those that have paid fines to settle federal charges that they illegally promoted sales. For the past year, a major federal investigation has been going on in Nevada, examining whether Biotronik was improperly paying doctors to use its pacemakers and defibrillators.

In South Florida, a former Miami technician for Ela Medical, maker of cardiac devices, filed a whistleblower complaint about the company using several schemes to pay kickbacks to doctors — allegations that Ela settled for $9.2 million in 2010. At Jackson Memorial, a 2006 ethics probe focused on University of Miami cardiologist Alberto Interian Jr., who acknowledged his girlfriend was the St. Jude sales rep. He said it was mere coincidence that during their relationship St. Jude sales at Jackson soared by 400 percent.

The county ethics commission decided Interian had not violated government conflict of interest codes because he was not a Jackson employee. In 2009, the commission urged Jackson to adopt a policy that would extend its ethics policies to nongovernment employees, but earlier this month, Jackson spokesman Edwin O’Dell said Jackson still doesn’t require outside doctors to sign codes of conduct.

Medical-device sales reps and doctors often work closely together, with the rep going into the operating room to make sure that the device is working properly before it is implanted. Sabbota and St. Jude’s sales rep, Charles Lodowski, generally work side by side in operating rooms, said Memorial spokeswoman Baldwin.

The pair, state corporate records show, also developed a working relationship outside the hospital. They are partners in two corporations, HTW Froyo and HTW2 Froyo. A 2011 Palm Beach Post story on “the yogurt craze” said Sabbota and Lodowski had bought franchise rights to three Menchie’s frozen yogurt shops. One was open at PGA Commons and another was planned to open in Wellington.

The Post article noted that Sabbota was a cardiologist. He told the reporter: “You don’t put a lot of smiles on people’s faces in medicine any longer. For a long time I’ve been looking at getting into something that would add to my ability to support myself and my kids, but also something I would enjoy.”

Sabbota, 44, who lives in Plantation, is one of two doctors in Cardiovascular Specialists of South Florida, which has an office in Davie. He obtained his Florida medical license in 2001. State and Broward County court records show no public complaints or malpractice suits.

In a phone conversation with The Miami Herald, Sabbota denied any wrongdoing and said he would have a lawyer call the reporter. But neither an attorney nor the doctor responded to five follow-up calls over two weeks. He also did not respond to two emailed lists of questions, including whether he informs patients about his relationship with the sales rep.

Lodowski also did not respond directly to five calls over two weeks. When The Miami Herald tried to reach him through the Memorial Healthcare System, spokeswoman Baldwin responded: “I did reach out to Charles and he said to refer you to St. Jude’s public relations department.”